Elevator



Nov. 26, 1940. H. RAYMOND 2,222,685

ELEVATOR Filed April 19, 1959 Fig.1.

INVENTOR Hug/2 Raymond Patented Nov. 26, 1940 2,222,685

UNITED STATES, PATENT OFFICE.

I ELEVATOR v 7 Hugh Raymond, Pittsburgh, Pa, assignor to'Ra'ymond Brass & Mfg. (30., Pittsburgh, Pan, a

partnership consisting of Ross Raymond and Isaac Raymond Application' April 19, 1939, seriaiNm-zsaew I 3 Claims. (01 .1s7h17 This invention relates to dumb waiters or Toinsure a tight contact between the plunger elevators of the type shown in United States M and the-interior of the. tubular guide 8, the Patent No. 855,0'7 iin which a load carrying car lower end of theplunger l4 carries leather cups is suspended by a pulley and cable arrangement I50 andv 55b The cup l5 a opens upwardly to 5 and is counterweighted by 'a piston or plunger prevent air'from, passing the plunger when it is 5 which, in turn, is actuated in a cylinder by fluid raised in the tubular guide. The cupl5b-opens pressure. The plung'erhas a weight greater than downwardly to seal off the water which is adthe car plus its maximum load so that the car mitted intojthetubular guide to'raise the plunger. is raised by the action of gravity on the plunger. A drain pipe I6 is provided in the upper-portion 0 The car is lowered when the plunger is raised of the guide 8 to carry off any water which 0 by fluid pressure. may leak past they leather cups I5. I

I have developed improvements in this type Figure z'illustrates' a form of three-way valve of dumb waiter which provide a smoother car Which may be-uSed o Control the admission o operation than has heretofore been possible and fluid under pressure into the guide 8. By means thus eliminate severe strains on the moving parts, of t e Va ve l the guide Remedy b Connected-t0 15 particularly on the cable and the cable conneca S ureehf Water pressureby h inlet p p is tions. In addition, the operation of the dumb or to fla waste' line by an outlet pipe IS; The waiter is made more safe. valve I! is turnediby a handle mounted on a In the accompanying drawing I have illusvertical rod ;2 l. The rodxzl may be made any 20 trated certain present preferred embodiments of u a eileh and a r m of handles 20 20 my invention. Inthe drawing: may be placed-thereon so that the movement of Figure l is a broken elevation view of my elethe car 5 can becontrolled from as many posi-- vator with parts broken away tobetter illustrate tio s as de iredxi- InFiguIe 2 the handle S Wn the mechanism thereof; as turned to the position marked A, thereby'per- Figure 2 is a section along the lines IIII of m tting water under Pressure to flow from the 25- Figure 1; inlet pipe 18 through the pipe 22 into'the lower Figure 3 is a' vertical section of a valve which e d of t e guide The Water raises the plunger is used with my elevator; and I and therefore the car will descend. When the Figure 4 is a broken elevation view of a modihandle 20' is turned to the position marked B the fication of my elevator. pipe 22 is connected to the outlet pipe l9 and the 30 In Figure 1 I have shown'an elevator having plunger M will descend, raising thecar 5 and a car 5 which is raised and lowered in a shaft 6 forcing water out of the guide 8. When the being guided therein by guides 1 and 8. The handle 29 S in the Position marked C the p p guides 1 and 8 extend the entire length of the Z2 is eutofif em bo t e inlet p p d t shaft and are secured at their upper ends to a outlet pipe l9 and the car 5 will remain 35 beam' 9. The car 5 carries shoes l0 which enst ygage the guides 1 and 8 and hold the car in AS Shown in F u e 1 t guide Contains W position. springs 23 and24 whichare designed to stop the .Th car 5 is supported by a cable ll fastened plunger M at each end of its path of-travel. The

40 to a yoke Ha which is secured to the top of the sp g-Z S heldih the pp end f t e u de 8 40 car 5. Thecable H passes over two pulleys l2 by a limit 1010011125v The p is held in a and I3, rotatablymounted on the beam 9, and Sp g el'l bolted to t e botto of the passes down inside the tubular guide 8 where uide 8. by means of fl e 1- When the it is secured to a plunger I4 reciprocable in the p u er l4 app o c the p the bottom guide. The plunger I4 is so designed that its of the'guide B it engages -Sp g Z e 45 weight exceedsthe combined weight of the car 5 sp 24 and compresses t sp by r ason and the maximum load which it is intended shall of its kinetic energy. As the springs are combe carried in the car; pressed, resistance to further compression in- Since the weight I4 is heavier than the car 5 creases so that the plunger is gradually de- 60 and its lead. he ear is raised by the action of celerated until it stops. Sudden stops are gravity alone. To lower the car I admit a suitavoided thus eliminating bouncing of the car able fluid, preferably water, under pressure into and severe strains on the cable and the cable the tubular guide beneath the plunger M. The connections. This feature is of special imfluid under pressure will raise the plunger l4 portance in dumb waiters where it is desirable to and thus lower the car. keep the cost of construction and maintenance 55 as low as possible and to therefore use only one cable for supporting the car.

When the plunger I4 is stopped by the spring 23 at the bottom of the guide 8, the car will automatically come to rest at the top of the shaft. It will not be necessary for the operator to turn the valve I1 into the neutral, position. In. such case, if the car 5 is loaded to such an extent that the weight of the car plus the weight of the load which is placed in it exceeds the weight of the plunger [4, the car will descend. The plunger [4 will rise and suck water and air through the pipe 22 and outlet pipe l9 into the tubular guide 8. To prevent the car from descending independently of the will of the operator I connect a check valve 28 into the fluid outlet pipe l9. As shown in Figure 3, the valve 28 may be of the type in which a valve stem 29 is seated and held on a valve seat 30 by its own weight. When the plunger l4 descends in the guide 8 water flows through the pipe I9 in the direction shown by the arrow marked D in Figure 3. The flow of water raises the valve stem 29 to permit the water to flow through the check valve 23. If the car 5 is overloaded when at the top of the shaft 6, the plunger M will rise. Since the valve 28 is normally closed a vacuum will be created in the guide 8 beneath the plunger [4 and since the guide 8 is open to the atmosphere at its upper end the vacuum created in the guide 8 beneath the plunger 14 will prevent the weight from rising and will hold the car 5 at the top of the shaft.

As above described, when the plunger l4 descends in the guide 8 and strikes the spring 23 its kinetic energy will compress the spring 23 until this energy is absorbed. The spring 23 will then expand and raise the plunger It a slight distance. Because of the check valve 28 a partial vacuum will be created in the spring chamber 26. When the valve I I is turned to admit water under pressure into the pipe 22 to raise the plunger M a water hammer will result because of the vacuum created in the spring chamber 26 when the plunger 14 was raised by the spring 23. To eliminate this water hammer I connect an air chamber 3| into the pipe 22 between the spring chamber 26 and the valve l1. When water is forced out of the guide 8 by a downward movement of the plunger M- a certain amount of water will be forced into the air chamber 3| and the air therein will be compressed. When the plunger M is raised by the spring 23 the water and compressed air in the chamber 3| will flow into the spring chamber 26 and thus prevent a water hammer when water under pressure is admitted into the spring chamber 26.

Figure 4 shows a modification of my elevator which is similar to the elevator shown in Figure 1 except that the plunger l4 reciprocates in a cylinder 32 separate from the guides I and 8. The cylinder 32 is mounted vertically and is preferably adjacent the shaft in which the elevator car travels.

By virtue of the improvements which I have described above, a dumb waiter driven by fluid pressure may be operated with greater safety and with greater smoothness of movement, particularly when the car is at the ends of its path of travel. The limit springs in the cylinder in which the plunger moves provide a gradual deceleration of the plunger when it reaches the top or bottom of the cylinder and thus prevent a sudden jarring stop which will make the car bounce and impose severe strains on the cable and cable connections.

The check valve in the fluid outlet pipe prevents the car from descending if it is overloaded when at the top of the shaft and the air chamber prevents a water hammer when fluid under pressure is admitted into the cylinder to raise the plunger from the bottom of the shaft.

While I have described certain present preferred embodiments of my invention it is to be distinctly understood that it may be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

1. An elevator comprising a vertically movable car, a plunger, a pulley and cable suspension for said car, one end of said cable being attached to the car and the other end being attached to the plunger, a cylinder in which the plunger reciprocates, means for controlling the admission of fluid under pressure to the cylinder to raise the plunger and permit the car to descend, means at each end of the cylinder to decelerate the motion of the plunger before it reaches the upper 1 and lower limits of its path of travel therein,

safety means for preventing the car from descending if it is overloaded when at rest at the upper limit of its path of travel, and an air chamber in communication with said cylinder between said cylinder and safety means.

2. An elevator comprising a vertically movable car, a plunger, a pulley and cable suspension for the car, one end of the cable being attached to the car, the other end being attached to the plunger, 2. cylinder in which the plunger reciprocates, means connected to fluid inlet and fluid outlet pipes for controlling the flow of fluid under pressure into and out of said cylinder whereby the admission of fluid under pressure raises said plunger and permits the car to descend, and a check valve in the fluid outlet pipe for preventing backflow through the pipe into said cylinder.

3. An elevator comprising a vertically movable car, a plunger, a pulley and cable suspension for the car, one end of the cable being attached to the car, the other end being attached to the plunger, a cylinder in which the plunger reciprocates, means connected to fluid inlet and fluid outlet pipes for controlling the flow of fluid under pressure into and out of said cylinder whereby the admission of fluid under pressure raises said plunger and permits the car to descend, springs at each end of the cylinder to decelerate the motion of the plunger before it reaches the upper and lower limits of its path of travel in the cylinder, a valve in the fluid outlet pipe for preventing backflow through the pipe into said cylinder, and an air chamber in communication with the cylinder between the cylinder and the valve in the fluid outlet pipe.

HUGH RAYMOND. 

